Compact, high-power laser systems typically rely on in-line systems, which have obscurations such as secondary mirrors, struts holding the system mirrors, and the like. The energy blocked by the obscurations may be scattered back into the system, causing substantial system heating. To address this issue, conventional obscured laser systems implement one or more existing solutions, including long cycle times and a beam dump. Off-axis laser systems may also be used to avoid the obscuration entirely.
Thus, some obscured laser systems provide long cycle times, thereby allowing the systems sufficient time to cool between shots. However, long cycle times have disadvantages that include a reduction in system effectiveness.
For systems including a beam dump, heat may be transferred out of the system using the beam dump. For example, some laser systems implement a cooling block that provides radiative or liquid cooling. However, such a cooling block requires cooling lines and pumps. In addition, using a cooling block reduces cycle time while waiting for the cooling block to cool and reduces the length of on time for the laser system. The complexity of a beam dump also reduces system reliability.
Off-axis systems attempt to avoid any obscurations that would require a beam dump by arranging the components off-axis from each other. However, off-axis systems typically require more space and are more difficult to align. In addition, the off-axis mirror sections are harder to manufacture and test.